A device described in Japanese Patent Application Publication No. 2007-270865 (JP 2007-270865 A) (Patent Document 1) is known as an example of the speed change device described above. The structure disclosed in Patent Document 1 will be described below with reference to FIG. 6 of the present application which is a reprint of FIG. 3 of Patent Document 1. As illustrated in FIG. 6, the speed change device according to Patent Document 1 includes a planetary gear mechanism disposed coaxially with a power transfer shaft, and the planetary gear mechanism includes a carrier that rotatably supports a pinion. The speed change device includes a structure for leading oil supplied through the inside of the power transfer shaft to a carrier shaft to lubricate a support portion of the carrier shaft for the pinion. An oil receiving portion is provided at a portion of the radially inner portion of the carrier, which opposes an in-shaft oil passage formed in the power transfer shaft, and oil is supplied from the oil receiving portion, achieving good lubrication of the support portion for the pinion.
In the device according to Patent Document 1, the oil receiving portion is formed in a recessed shape between a spline engagement portion on the carrier side for engagement with a tubular shaft member disposed coaxially with the power transfer shaft and a race abutment portion that abuts against a thrust bearing. In the device according to Patent Document 1 configured in this way, in order to secure the depth of the oil receiving portion in a recessed shape, the race abutment portion is formed to extend in the radial direction to the vicinity of the outer peripheral surface of the power transfer shaft. As a result, the race abutment portion of the carrier is configured to project toward the radially inner side of the spline engagement portion.
With such a configuration, the race abutment portion physically obstructs formation of a spline engagement portion for engagement with the tubular shaft member on the carrier, and broaching may not be applied. Therefore, it is necessary to perform shaping, which does not provide a high productivity. Meanwhile, simply shortening the projection length of the race abutment portion toward the radially inner side makes the oil receiving portion shallower. Therefore, a sufficient amount of oil may not be received, as a result of which it is difficult to secure good lubrication of the support portion for the pinion.